Arthur Ramos Reyes

I investigate how toxic metals affect vacuole inheritance and structure in Saccharomyces cerevisiae. The vacuole is an essential organelle that maintains cellular homeostasis through nutrient storage, recycling, and detoxification. Exposure to excess metals disrupts vacuole structure and inheritance, preventing daughter cells from receiving this organelle and compromising their viability.

Organelle inheritance is a tightly regulated process that ensures daughter cells receive essential cellular structures during division, and defects in this process compromise cell viability. The yeast vacuole, a membrane-bound organelle homologous to the mammalian lysosome, is critical for cellular homeostasis, degradation, and metal detoxification. While metals are essential for life, excess exposure disrupts cellular processes through nonspecific interactions with proteins. In Saccharomyces cerevisiae, lithium and magnesium disrupt vacuole inheritance from mother to daughter cells. Lithium is proposed to inhibit GSK3, blocking phosphorylation of proteins required for inheritance, whereas magnesium activates GSK3 yet also disrupts inheritance. Additionally, although the vacuole is considered a primary site of metal storage, direct evidence of subcellular metal accumulation is limited. This project investigates whether phosphorylation of key regulatory proteins is sufficient to restore inheritance, how lithium–magnesium interactions affect inheritance, and direct analysis to determine if the vacuole serves as the primary metal storage site. Using genetic manipulation, metal treatments, and fluorescence-based confocal microscopy, this work investigates how toxic metals alter organelle dynamics under cellular stress.